JPH08188132A - Brake system equipped with automatic braking device - Google Patents

Abstract

PURPOSE: To operate an automatic brake surely at the time of the operation of a normal brake as well as to enable it to operate the normal brake surely at the time of operation of the automatic brake, respectively. CONSTITUTION: Master cylinder pressure to be produced by operation on a brake pedal 1 is fed to each wheel cylinder via both first and second brake passage 6, 7, first and second center valves 26', 26 of an automatic brake actuator 8, and both first and second output ports 24' and 24, whereby a normal brake operates. In addition, when an electronic control unit 40 operates a thrust generator 38, automatic brake operation signal pressure is produced there, and with this pressure, both first and second small and large diametral pistons 18', 18; 16', 16 advance forward and thereby the first and second center valves 26' and 26 are closed, and the generating pressure is fed to each wheel cylinder, whereby an automatic brake operates. At the time of operation of the normal brake, if the thrust generator 38 operates the automatic brake actuator 8, the automatic brake operates, and further at the time of operation of the automatic brake, the normal brake is operated by the operation on the brake pedal 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to easily start a vehicle, such as an automobile, on a slope, and to eliminate the need to wait for a signal or to continue to depress the brake pedal on a congested road. In order to control the traction during idling of the vehicle, to keep the vehicle stopped on a slope, to control the distance between vehicles while traveling, to suppress the traveling speed of the vehicle such as overspeed prevention on a downhill, or on the side The present invention relates to a brake system including an automatic braking device used to prevent forgetting to apply a brake.

[0002]

2. Description of the Related Art Recently, in automobiles, it is possible to easily start a vehicle such as an automobile on a slope without requiring a sudden pedal change operation from a parking brake or a brake pedal to an accelerator pedal. For,
In order to reduce the fatigue caused by brake operation by eliminating the need to operate the brake pedal while waiting for traffic lights and in congested roads, traction control should be performed when the drive wheels run idle to ensure proper start and acceleration. In order to ensure that the vehicle is stopped on a hill, the inter-vehicle distance is automatically controlled while driving, and the vehicle traveling speed is controlled to prevent overspeed on a downhill. Brake systems have been developed that are equipped with an automatic braking device that is used to automatically prevent the vehicle from forgetting to apply the side brakes.

As a brake system provided with such an automatic brake device, a conventional brake system as shown in FIG.
There is a brake system disclosed in Japanese Patent Publication No. 292256.

The brake system shown in FIG. 5 is equipped with a tandem type vacuum booster. In this state, the vacuum booster 150 has a chamber mechanism in which the atmosphere valve 151a of the valve mechanism 151 is closed and the vacuum valve 151b is opened. A vacuum is introduced to A, B, C, and D, and the brake is in a non-operating state. Further, the solenoid valve 152 is normally set to the position shown in the figure,
Therefore, a vacuum is normally introduced into the chamber A ′ surrounded by the bellows 153.

When the brake pedal (not shown) is depressed and the input shaft 154 moves forward during normal braking in this brake non-operating state, the atmospheric valve 15 of the valve mechanism 151.
Since 1a is opened and the vacuum valve 151b is closed, the atmosphere is introduced into the variable pressure chambers B and D through the variable pressure passages 155 and 156, respectively. As a result, a differential pressure is generated between the chambers A, B and C, D before and after the diaphragms 157, 158, and the diaphragms 157, 158 and the power pistons 159, 160.
Moves forward, an output is generated from the output shaft 161, and the master cylinder 162 operates due to this output, and the normal brake operates.

The advance of the diaphragms 157, 158 and the power pistons 159, 160 is continued until the atmosphere valve 151a is closed and the atmosphere is not introduced into the variable pressure chambers B, D. As a result, the output depends on the input, that is, the brake pedal depression amount. The output is a predetermined servo ratio. In this state, the atmosphere valve 151a and the vacuum valve 151 of the valve mechanism 151 are
Both b are in the closed state.

On the other hand, in the brake non-operating state, when the controller switches the solenoid valve 152 under the automatic brake operating condition, the atmosphere is introduced into the chamber A ', and this atmosphere further causes the constant pressure passage 163 and the open vacuum valve. It is introduced into the variable pressure chambers B and D through the variable pressure passages 155 and 156, respectively. As a result, the diaphragms 157, 158 and the power pistons 159, 160 move forward and the brake operates, as in the normal braking described above. In this way, when the automatic brake operating condition is satisfied, the solenoid valve 152 is switched by the control signal from the controller, whereby the automatic braking is activated.

[0008]

By the way, in the conventional brake system including the automatic brake device, when the driver depresses the brake pedal to perform the normal braking, the vacuum valve 151b is closed and the constant pressure passage 163 is provided. The variable pressure passage 155 is in a disconnected state. Therefore, even when the driver is stepping on the brake pedal, the automatic brake operation condition is established, and even if the controller switches the solenoid valve 152 to introduce the atmosphere into the chamber A ′ and the constant pressure passage 163, the atmosphere is transformed into the variable passage 155. Will not be introduced to. Therefore, when the driver depresses the brake pedal, the automatic brake cannot be operated even under the automatic brake operating condition.

The present invention has been made in view of such a problem, and an object thereof is to further reliably operate the automatic brake even when the normal brake is actuated by stepping on the brake pedal, and to automatically actuate the automatic brake. It is another object of the present invention to provide a brake system including an automatic braking device that can reliably operate a normal brake even at times.

[0010]

In order to solve the above-mentioned problems, a first aspect of the present invention provides a brake operating member, a master cylinder for generating a master cylinder pressure by the brake operation of the brake operating member, and the master. A brake passage for supplying a cylinder pressure, a brake cylinder that is supplied with the master cylinder pressure to generate a braking force for applying a normal brake to a wheel, and an automatic brake actuator provided in the brake passage. The automatic brake actuator includes a thrust generator that generates thrust for operating the automatic brake actuator and a control device that controls the operation of the thrust generator. The automatic brake actuator includes a housing and a large diameter hole and a small diameter hole formed in the housing. A stepped hole consisting of a hole and a large-diameter hole are provided so as to be liquid-tight and slidable. Diameter piston, a small-diameter piston slidably and slidably disposed in the small-diameter hole and having one end abutting one end of the large-diameter piston to advance the large-diameter piston, and the brake formed in the housing An automatic brake actuator inlet communicating with the output port of the master cylinder through a passage and communicating with the large diameter hole on one end side of the large diameter piston, and with the large diameter piston formed in the housing and communicating with the wheel cylinder. An automatic brake actuator output port that communicates with the large diameter hole on the other end side, and normally opens to communicate the automatic brake actuator inlet and the automatic brake actuator output port, and the automatic brake actuator output port of the large diameter piston Closes when moving forward in the direction Normally open on-off valve for blocking and the automatic brake actuator output port and,
An automatic brake actuation signal pressure generating piston that generates an automatic brake actuation signal pressure by being brought into contact with the output rod of the thrust generator and advanced by the thrust of the thrust generator, and the automatic brake actuation signal pressure of the small diameter piston. It is characterized by comprising an automatic brake actuation signal pressure introduction passage introduced at the other end.

The invention according to claim 2 is characterized in that the on-off valve is constituted by a center valve provided on the large-diameter piston. Further, the invention of claim 3 is
The automatic brake actuator is provided for each of the brake passages of each of these brake systems, and the automatic brake actuation signal pressure introduction passage applies the automatic brake actuation signal pressure to each of the automatic brake actuators. It is characterized in that it is formed in a passage commonly introduced to the other end of the small diameter piston.

According to a fourth aspect of the present invention, the housing of each automatic brake actuator is a common housing, and the automatic brake operation signal pressure introducing passage and the automatic brake operation signal pressure generating piston are provided in this housing. The large-diameter pistons and the small-diameter pistons of the automatic brake actuators are coaxially provided, and the automatic brake actuation signal pressure introduction passage is provided at the other end of the small-diameter pistons of the automatic brake actuators. It is characterized by being formed in a T-shaped passage so as to communicate with each other. Further, in the invention of claim 5, the power of the thrust generator is negative pressure, compressed air, hydraulic pressure,
It is characterized by being either power by an electric motor or electromagnetic force.

[0013]

In the present invention thus constructed, in the case of a normal brake, the master cylinder pressure is generated by the brake operation of the brake operating member, and this master cylinder pressure is applied to the brake passage and the automatic brake actuator inlet. Is supplied to the brake cylinder via the normally open on-off valve and the automatic brake actuator output port,
Braking is normally done. When the automatic brake operating condition is satisfied, the control device operates the thrust generator, the thrust generator generates thrust, and the thrust causes the automatic brake actuation signal pressure generating piston to move forward. Then, the forward movement of the piston generates an automatic brake actuation signal pressure, and the small diameter piston and the large diameter piston advance due to the automatic brake actuation signal pressure. The forward movement of the large-diameter piston closes the on-off valve to generate automatic brake pressure, and this automatic brake pressure is sent to the brake cylinder to perform automatic braking.

Further, when the automatic brake operating condition is satisfied during the normal brake operation by depressing the brake pedal, the automatic brake operating signal pressure generating piston moves forward by the thrust of the thrust generator to generate the automatic brake operating signal pressure as described above. To do. While the automatic brake actuation signal pressure is smaller than the master cylinder pressure generated by the depression of the brake pedal, the small diameter piston and the large diameter piston do not move forward, and the brake cylinder pressure is kept constant at the master cylinder pressure. When the automatic brake actuation signal pressure becomes equal to or higher than the master cylinder pressure, the small diameter piston and the large diameter piston move forward to generate pressure. This pressure causes the brake cylinder pressure to increase linearly with increasing thrust. At this time, the pressure of the brake cylinder for the same thrust of the thrust generator is higher than the brake cylinder pressure when only the automatic brake is operating, and the automatic brake operation that occurs in the operation of only the automatic brake from the brake cylinder pressure when the brake pedal is depressed. It becomes higher by the pressure less the brake cylinder pressure when the signal pressure becomes the master cylinder pressure.

When the brake pedal is depressed during the automatic brake operation, the master cylinder generates a master cylinder pressure as described above, and this master cylinder pressure is introduced to one end of the large-diameter piston of the automatic brake actuator. Since the on-off valve is closed by the automatic brake operation, the master cylinder pressure acts on the large-diameter piston in the direction of advancing the large-diameter piston together with the automatic brake operation signal pressure. As a result, the brake cylinder pressure increases linearly at the same time as the master cylinder pressure increases. Therefore, when the brake pedal is depressed, the normal brake operates together with the automatic brake, and good responsiveness is obtained. The slope of the increase in the brake cylinder pressure at this time acts in such a direction that the master cylinder pressure causes the small-diameter piston that presses the large-diameter piston to retract due to the automatic brake actuation signal pressure, so the increase in the normal brake only It is smaller than the slope. When the master cylinder pressure rises and becomes equal to the brake cylinder pressure, the brake cylinder pressure rises in proportion to the rise of the master cylinder pressure. Thus, when the normal brake is activated during automatic braking, the braking force is increased by the normal braking.

Further, even if a normal brake component such as a master cylinder fails, the thrust generator operates and the automatic brake actuation signal pressure is generated, so that the automatic brake operates, and the thrust generator and the automatic brake operate. Even if an automatic brake component such as an actuator fails, the master cylinder pressure is generated by depressing the brake pedal, so that the normal brake operates. As a result, the brake system of the present invention has a fail safe function.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a braking system including an automatic braking device according to the present invention.

As shown in FIG. 1, a brake system equipped with an automatic brake device according to this embodiment has a brake pedal 1, which is a brake operating member for applying a normal brake as in the conventional normal brake device, and the brake pedal. A conventionally known single-type or tandem-type negative pressure booster 2 that boosts the pedaling force of 1 by a predetermined servo ratio and outputs it, and operates by the output of the negative pressure booster 2 to generate a brake pressure. A conventionally known tandem master cylinder 3 is provided. One side of the first and second brake passages 6 and 7 is connected to the two first and second output ports 4 and 5 of the tandem master cylinder 3, respectively, and these first and second brake passages are connected. The other side of 6, 7 is connected to an automatic brake actuator 8 which generates the brake pressure of the automatic brake.

The automatic brake actuator 8 has a first inlet 9 which is connected to the first brake passage 6.
It is composed of a cylinder portion 10, a second cylinder portion 12 having a second inlet 11 connected to the second brake passage 7, and a third cylinder portion 13 that generates an automatic brake actuation signal pressure.

Although the first and second cylinder portions 10 and 12 have exactly the same structure, they are provided symmetrically and coaxially with each other. As shown in detail in FIG. 2, the second cylinder portion 12 includes the first to third cylinder portions 10, 12,
Second stepped hole 1 formed in a common housing 14 of 13
The second large-diameter piston 16 is fitted in the large-diameter hole of the second stepped hole 15 by the second cup seal 17 so as to be liquid-tight and slidable. Further, the second small-diameter piston 18 has the second small-diameter O-ring 19 in the small-diameter hole of the second stepped hole 15.
Is fitted so as to be liquid-tight and slidable. In that case, the second small-diameter piston 18 is arranged coaxially and in series with the second large-diameter piston 16.

A second master cylinder pressure introducing chamber 20 communicating with the second inlet 11 is formed in the second stepped hole 15 between the second large and small diameter pistons 16 and 18.
The master cylinder pressure (hereinafter, also referred to as MCY pressure) of the tandem master cylinder 3 is introduced into the master cylinder pressure introduction chamber 20 through the second output port 5, the second brake passage 7 and the second inlet 11. There is. The opening end of the second stepped hole 15 is liquid-tightly closed by the second plug 21 and the second large-diameter O-ring 22. A second automatic brake pressure generating chamber 23 is formed in the second stepped hole 15 between the second plug and the second large diameter piston 16, and the second automatic brake pressure generating chamber 23 is the second automatic brake pressure generating chamber 23. The brake actuator output port 24 communicates with a second wheel cylinder (W / C) (not shown).

The second large-diameter piston 16 has a second stage which axially penetrates the second large-diameter piston 16 to connect the second master cylinder pressure introducing chamber 20 and the second automatic brake pressure generating chamber 23. The through hole 25 is provided, and the normally open second center valve 26, which is the on-off valve of the present invention for opening and closing this second step through hole 25, is provided. The center valve 26 is formed in the large-diameter hole of the second stepped through hole 25, and the second valve element 27 is formed on the stepped portion of the second stepped through hole 25 so that the second valve element 27 can be seated. Second valve seat 28 and a second rod extending from the second valve body 27 through the small diameter hole of the second stepped through hole 25 and longer than the length of the small diameter hole of the second stepped through hole 25. 29 and a second valve body biasing spring 30 that constantly biases the second valve body 27 toward the second valve seat 28. A second piston urging spring 31 is contracted between the second large-diameter piston 16 and the second plug 21, and the second large-piston urging spring 31 causes the second large-diameter piston 16 to move to a second position. The master cylinder pressure introducing chamber 20 is constantly urged, and when the brake is not operated, the second large-diameter piston 16 is set so as to be in the non-operating position in contact with the stepped portion of the second stepped hole 15. There is. Then, in this non-actuated position of the second large-diameter piston 16, the second
The tip of the rod 29 comes into contact with the step portion of the second stepped hole 15, whereby the second valve body 27 is separated from the second valve seat 28 and the second valve seat 28 is released.
The center valve 26 is opened and the second stepped through hole 25 is opened.

Further, since the first cylinder portion 10 has the same structure as the above-mentioned second cylinder portion 12, a detailed description thereof will be omitted, but in the following description of the embodiments, each constituent element of the first cylinder portion 10 will be described. Second, to make it easier to understand
The first cylinder part 1 corresponding to the components of the cylinder part 12
Each constituent element of 0 is expressed as "first" instead of "second", and "'" is added to the reference numeral of the constituent element of the second cylinder portion 12. That is, the first stepped hole 15 ', the first large diameter piston 16', the first cup seal 17 ', the first small diameter piston 18', the first small diameter O-ring 19 ', the first master cylinder pressure introducing chamber 20', First plug 21 ', first large-diameter O-ring 22', first automatic brake pressure generating chamber 23 ', first automatic brake actuator output port 24', first stepped through hole 25 ', first center valve 26'. , The first valve body 27 ',
The first valve seat 28 ', the first rod 29', the first valve body biasing spring 30 ', and the first piston biasing spring 31'. Although some of the reference numerals of the respective constituent elements of the first cylinder brake 10 are not shown, they are used in the description of the embodiments for easy understanding.

Further, as shown in FIG. 1, the third cylinder portion 1
3, the housing 14 has first and second stepped holes 15 ',
A third hole 32 formed in a direction orthogonal to 15 is provided, and an automatic brake actuation signal pressure generating piston 33 is liquid-tightly and slidably fitted in the third hole 32. The third above the automatic brake actuation signal pressure generating piston 33
An automatic brake actuation signal pressure generation chamber 34 is formed in the hole 32, and the automatic brake actuation signal pressure generation chamber 34 is formed through a passage 35 and a T-shaped passage 36 in the first and second small diameter pistons 18 ′, 18. The first and second master cylinder pressure introducing chambers 20 ', 20 communicate with the end surface on the opposite side. The passage 35 and the T-shaped passage 36 form the automatic brake actuation signal pressure introduction passage of the present invention. The automatic brake actuation signal pressure generating piston 33 is constantly urged downward by the return spring 37, and is set to the inoperative position at the lowermost end position of the third hole 32 shown when the automatic brake is inoperative. There is.

At the lower end of the third cylinder brake 13,
The thrust generator 38 is fitted and fixed. Although the thrust generator 38 is not shown in detail, for example, negative pressure, compressed air,
The thrust generator 38 is a conventionally known thrust generator that generates thrust by power such as hydraulic pressure, an electric motor, or electromagnetic force.
The output rod 39 of the automatic braking signal pressure generating piston 3
3, the automatic braking actuation signal pressure generating piston 33 is actuated via the output rod 39 by the generated thrust. The thrust generator 38 is electrically connected to an electronic control unit (hereinafter also referred to as an ECU) 40, and its operation is controlled by the ECU 40. In that case, the ECU 40 controls opening / closing of an electromagnetic on-off valve (not shown) when the power for operating the thrust generator 38 is fluid pressure, and when the power source for operating the thrust generator 38 is an electric motor, for example. Controls the drive of this electric motor, or controls the excitation of the electromagnetic solenoid when the power for operating the thrust generator 38 is an electromagnetic force. Then, the ECU 40, for example, each wheel speed sensor, clutch stroke sensor, clutch switch, neutral switch, stop lamp switch,
The thrust generator 38 is controlled so as to be calculated based on the signals from the parking brake switch and the door switch, and when it is determined that the automatic brake operating condition is satisfied based on the calculation result. The automatic brake operating conditions include the conditions for starting a slope, the conditions for holding a braking condition in a signal waiting state and a traffic jam, the conditions for performing traction control, and the conditions for holding a vehicle stopped on a slope. There are conditions, conditions for controlling the inter-vehicle distance during traveling, conditions for suppressing the traveling speed of the vehicle, conditions for preventing forgetting to apply the side brake, and the like.

In the braking system having the automatic braking device of the present embodiment constructed as described above, the ECU 40 does not drive the thrust generator 38 when the normal brake and the automatic brake shown in FIG. The device 38 outputs nothing. As a result, the automatic brake actuation signal pressure generating piston 33 of the automatic brake actuator 8, the first and second small diameter pistons 18 ', 18 and the first and second large diameter pistons 16', 16 are both in the inoperative position. , First and second center valves 2
6 ', 26 are open and the automatic brake actuator 8 does not output anything. Further, the brake pedal 1, the negative pressure booster 2 and the tandem master cylinder 3 are also in the non-actuated position, and no brake pressure is normally generated.

When the brake pedal 1 is depressed to apply the normal brake in this state, the negative pressure booster 2
Outputs a boosted pedaling force at a predetermined servo ratio, and this output causes the tandem master cylinder 3 to generate MCY pressure P _M in each of the two pressure chambers. The MCY pressure P _{M in} one of the pressure chambers is transmitted through the first output port 4 and the first brake passage 6 to the first inlet 9 of the automatic brake actuator 8.
Is supplied to the first master cylinder pressure introducing chamber 20 ', the first stepped through hole 25', the open first center valve 26 ', and the first automatic braking pressure generating chamber 23. ', And the wheel cylinder pressure P _W (hereinafter, W) to the wheel cylinder (W / C) of one brake system via the first automatic brake actuator output port 24'.
/ C pressure), the wheel cylinder outputs the braking force, and the wheels of one brake system are normally braked.

At the same time, the MCY pressure P _M in the other pressure chamber is
It is supplied to the second inlet 11 of the automatic brake actuator 8 through the second output port 5 and the second brake passage 7, and further from the second inlet 11 to the second master cylinder pressure introducing chamber 20 and the second stepped penetration. W / to the wheel cylinder (W / C) of the other brake system via the hole 25, the opened second center valve 26, the second automatic brake pressure generating chamber 23, and the second automatic brake pressure actuator force port 24.
It is supplied as C pressure P _W , and its wheel cylinder outputs a braking force to normally brake the wheels of the other brake system.

When the brake pedal 1 is released to release the normal brake, the negative pressure booster 2 is deactivated and each pressure chamber of the tandem master cylinder 3 communicates with the reservoir 3a. Brake fluid supplied to the wheel cylinders of the
Automatic brake actuator output ports 24 ', 24, first
And second automatic brake pressure generating chambers 23 ', 23, first and second stepped through holes 25', 25, open first and second center valves 26 ', 26, first and second master cylinder pressures. Each pressure of the tandem master cylinder 3 is introduced through the introduction chambers 20 ', 20, the first and second inlets 9, 11, the first and second brake passages 6, 7, and the first and second output ports 4,5. Returning to the chamber and the reservoir 3a, the normal brake is released.

When the ECU 40 determines that the automatic brake operating condition is satisfied based on the detection signals from various sensors in the brake non-operating state shown in the drawing, the ECU 40 drives the thrust generator 38. Then, the thrust generator 38 causes the thrust F
This thrust F causes the automatic brake actuation signal pressure generating piston 33 of the automatic brake actuator 8 to move forward through the output rod 39. Due to the forward movement of the automatic brake actuation signal pressure generation piston 33, an automatic brake actuation signal pressure is generated in the automatic brake actuation signal pressure generation chamber 34, and the automatic brake actuation signal pressure is passed through the passage 35 and the T-shaped passage 36 to the first position. And the second small diameter piston 1
It is introduced at the end faces of 8 ', 18. As a result, the first and second small-diameter pistons 18 ', 18 and the first and second large-diameter pistons 16', 16 advance together and the first and second center valves 26 ', 26 of the first and second center valves 26', 26 The second valve bodies 27 ', 27 are seated on the first and second valve seats 28', 28 to close the first and second center valves 26 ', 26, respectively. First and second small diameter pistons 18 ', 1
8 and the first and second large-diameter pistons 16 ', 16 are further advanced to generate automatic brake pressures in the first and second automatic brake pressure generating chambers 23', 23, respectively. These automatic braking pressures are respectively the first and second
W from automatic brake actuator output port 24 ', 24
/ C pressure is supplied to each wheel cylinder, and each wheel cylinder automatically brakes the corresponding wheel.

When the automatic brake operating condition is canceled, E
The CU 40 deactivates the thrust generator 38, and the thrust F of the thrust generator 38 disappears. Then, the automatic brake actuation signal pressure generating piston 33 moves downward due to the spring force of the return spring 37 to the non-actuated position, and the automatic brake actuation signal pressure disappears. Therefore, the first and second large,
Small-diameter pistons 16 ', 16; 18', 18 are respectively the first
And the spring force of the second piston biasing springs 31 ', 31 brings them to the inoperative position shown, and the first and second center valves 26', 26 open. As a result, the first and second automatic brake pressure generating chambers 23 ', 23 communicate with the inactive tandem master cylinder 3, so that the brake fluid supplied to the wheel cylinders of each brake system is the normal brake described above. Similar to the case of releasing the above, the automatic brake is released by returning to the tandem master cylinder 3.

When the automatic brake operating condition is satisfied during the normal brake operation by depressing the brake pedal 1, the ECU 40 operates the thrust generator 38, and the thrust generator 38 outputs the thrust F, as in the case of the automatic brake described above. While outputting, the automatic brake actuation signal pressure is generated in the automatic brake actuation signal pressure generating chamber 34.

At this time, since the normal brake is operated by depressing the brake pedal, the MCY pressure P _M0 is introduced into the first and second master cylinder pressure introducing chambers 20 ', 20, and each wheel cylinder has W / C pressure P _W0
Is occurring. In that case, since both the first and second center valves 26 ', 26 are open, the MCY pressures P _{M0 of} the first and second master cylinder pressure introducing chambers 20', 20.
And W / C pressure P _W0 are equal. The MCY pressure P _M0 acts on the first and second small-diameter pistons 18 ′, 18 in the direction of the T-shaped passage 36, respectively. Therefore, after the automatic braking operation by the ECU 40 is started, the first and second small-diameter pistons 18 ′ are provided while the thrust F of the thrust generator 38 is smaller than the thrust f that generates the automatic braking operation signal pressure equal to the MCY pressure P _M0. , 18 does not move forward.
Therefore, as shown in FIG. 3, the W / C pressure P _W does not change at all even if the thrust F increases, and is maintained at a constant W / C pressure P _W0 corresponding to the amount of brake pedal depression during normal braking. To be done.

When the thrust force F of the thrust generator 38 exceeds the above-mentioned thrust force f, the first and second large and small diameter pistons 16 ', 1
6; 18 ', 18 both move forward, and the first and second center valves 26', 2 are moved in the same manner as in the case of the automatic braking described above.
6 close together. As a result, as shown in FIG. 3, the W / C pressure P _W increases in proportion to the increase in the thrust F of the thrust generator 38. In this case, compared to the operation of only automatic braking,
W / C pressure P _W is W / C pressure P when the brake pedal is depressed
_The W / C pressure P _W1 generated when the thrust F of the thrust generator 38 during automatic braking is the thrust f is increased by _W0 . The relationship between the thrust force f and the W / C pressure P _W1 is as follows: the first and second large pistons 16 ', 16; 18', 1
It is determined by the pressure receiving area A ₁ ; A _{2 of} 8 and the pressure receiving area A _{3 of the} automatic brake operation signal pressure generating piston 33, and P _W1 = [A ₂ / (A ₁ · A ₃ )] · f.

Thus, the automatic brake operates even during the normal brake operation, and the braking force is strengthened by the automatic brake. Even if the normal brake is released in this state, the automatic brake is actuated and the first and second center valves 26 ', 26 are closed, so that the automatic brake is maintained in the actuated state. Further, the release of the automatic brake after the operation of the normal brake is released is the same as the case where only the automatic brake is operated.

When the automatic brake is operated, when the normal brake is operated by depressing the brake pedal 1 to further increase the braking force, the MCY pressure P _M is generated in each pressure chamber of the tandem master cylinder 3 as described above. However, the normal brake operates together with the automatic brake. At this time, since the automatic brake is operating, the first and second
The center valves 26 ', 26 are both closed to generate automatic brake pressure in the first and second automatic brake pressure generating chambers 23', 23, and each wheel cylinder has a W / C equal to this automatic brake pressure. Pressure P _W0 is generated. And the MC caused by the depression of the brake pedal
The Y pressure P _M is the first and second master cylinder pressure introduction chambers 2
0 ', 20 introduced. With this MCY pressure P _M , the first
Since both the second large-diameter pistons 16 'and 16 are pressed in the forward direction, as shown in FIG.
In other words, the W / C pressure P _W immediately further increases from the above-mentioned W / C pressure P _W0 . In that case, MCY pressure P _M is W / C pressure P _W
While it is smaller, the W / C pressure P _W increases along the straight line represented by the following equation with respect to the increase of the MCY pressure P _M.
That is, the first and second large-diameter piston 16 ', 16 A ₁ a pressure receiving area of the, also the first and second small-diameter piston 1
_Assuming that the pressure receiving area of 8 ′, 18 is A ₂ , P _W = [(A ₁ −A ₂ ) / A ₁ ] · P _M + P _W0 Therefore, the rising gradient of W / C pressure P _W is The first and second large diameter pistons 18 ', 18 pressing the first and second large diameter pistons 16', 16 are retracted by the automatic brake actuation signal pressure. Only the piston 16 ', 1 normal brake becomes smaller than that during operation. In addition, W / C pressure P _W and MCY pressure P _M
When becomes equal to each other, the W / C pressure P _W increases in proportion to the MCY pressure P _M.

Thus, the braking force can be increased by the normal brake even during the automatic braking operation. In this state, the automatic brake is released and the first
And the second large and small diameter pistons 16 ', 16; 18', 18
Even when both of them are retracted to the non-actuated position and the first and second center valves 26 ', 26 are opened, the brake pedal 1 is still depressed, so that the brake is normally kept in the actuated state. Further, the release of the normal brake after the automatic brake is released is performed by the first and second center valves 26 ',
Since 26 is open, it is the same as the case of the normal brake described above.

Further, even when the propulsive force generator 38 or the third cylinder portion 13 fails, normal braking is surely performed by depressing the brake pedal 1.

As described above, according to the brake system including the automatic brake device of this embodiment, the automatic brake can be reliably operated when the automatic brake operating condition is satisfied during the normal brake operation. Further, when the brake force due to the brake pressure of the automatic brake is insufficient during the automatic brake operation, the normal brake can be operated by stepping on the brake pedal 1. At this time, since the W / C pressure immediately rises after the brake pedal 1 is depressed, a larger deceleration is immediately obtained by the normal brake operation, and the responsiveness becomes good. Therefore, when the driver depresses the brake pedal to increase the braking force during the automatic brake operation, no discomfort is felt and a good pedal feeling is obtained. Moreover, in the high-pressure region of the brake pressure, the W / C pressure becomes equal to the MCY pressure and does not become higher than this MCY pressure. Therefore, even if the automatic brake actuator 8 and the thrust generator 38 are provided, the pressure resistance of the wheel cylinder is reduced. Can be conventional. Therefore, the conventional wheel cylinder can be used as it is, and an increase in cost can be suppressed.

Furthermore, since the thrust generator 38 is arranged in common for the two brake systems, only one thrust generator 38 is required, and from this point also an increase in cost can be suppressed. Further, even if the propulsive force generator 38 for automatic braking or the third cylinder portion 13 fails, the brake by the normal brake is secured, so the brake system of this embodiment has a fail-safe function. .

Although the automatic brake actuator 8 of the present invention is provided in both of the two brake systems in the above-described embodiment, it may be provided in only one of the two brake systems. In that case, one of the two brake systems is associated with the drive wheels, the other of the two brake systems is associated with the driven wheels, and only the brake system corresponding to the drive wheels is provided with the automatic brake actuator 8 and the thrust generator 38.
By providing the above, the traction control by the brake as the automatic brake can be more effectively performed when the drive wheels tend to idle.

The present invention can be applied not only to the two-brake system but also to a simple one-brake system. In that case, it goes without saying that the master cylinder is formed in a single shape. Furthermore, the negative pressure booster 2 does not necessarily have to be provided and can be omitted.

Further, in the above-described embodiment, the third cylinder portion 1
3 is provided integrally with the first and second cylinder portions 10 and 12, the third cylinder portion 13 is provided separately from the first and second cylinder portions 10 and 12, and the passage 35
Also, the T-shaped passage 36 may be formed by piping such as a tube.

[0044]

As is apparent from the above description, according to the brake system including the automatic brake device of the present invention, the automatic brake can be reliably operated during the normal brake operation. You can strengthen your strength. Further, the normal brake can be reliably operated during the automatic brake operation, and the braking force can be increased by the normal brake operation.
In that case, the brake cylinder pressure can be made higher than the brake cylinder pressure when only the automatic brake is operated by the operation of the automatic brake when the normal brake is operated. Further, in the operation of the normal brake during the automatic brake operation, the normal brake can be operated together with the automatic brake at the same time when the brake pedal is depressed, and good response can be obtained. Therefore, when the driver depresses the brake pedal to increase the braking force during the automatic brake operation, no discomfort is felt and a good pedal feeling is obtained.

Further, even if an automatic brake component such as a propulsion generator fails, the brake can be secured by the normal brake, and even if the normal brake component such as the master cylinder fails, the automatic brake can be secured. The brake system of the present invention has a fail-safe function.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a braking system including an automatic braking device according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the automatic brake actuator in the embodiment shown in FIG.

FIG. 3 is a diagram showing the relationship between the thrust of the thrust generator and the wheel cylinder pressure when the automatic brake operates during the normal brake operation in the embodiment shown in FIG.

FIG. 4 is a diagram showing a relationship between a master cylinder pressure and a wheel cylinder pressure when a normal brake operates during automatic brake operation in the embodiment shown in FIG.

FIG. 5 is a diagram schematically and partially showing a braking system including a conventional automatic braking device.

[Explanation of symbols]

1 ... Brake pedal, 2 ... Negative pressure booster device, 3 ... Tandem master cylinder, 4 ... First output port, 5 ... Second output port, 6
... first brake passage, 7 ... second brake passage, 8 ... automatic brake actuator, 9 ... first inlet, 10 ... first cylinder portion, 11 ... second inlet, 12 ... second cylinder portion, 1
3 ... 3rd cylinder part, 14 ... Housing, 15 ... 2nd stepped hole, 15 '... 1st stepped hole, 16 ... 2nd large diameter piston,
16 '... 1st large diameter piston, 18 ... 2nd small diameter piston,
18 '... 1st small diameter piston, 20 ... 2nd master cylinder pressure introduction chamber, 20' ... 1st master cylinder pressure introduction chamber, 23
... second automatic brake pressure generation chamber, 23 '... first automatic brake pressure generation chamber, 24 ... second automatic brake pressure output port, 24'
... first automatic brake pressure output port, 25 ... second stepped through hole,
25 '... 1st stepped through hole, 26 ... 2nd center valve, 2
6 '... 1st center valve, 27 ... 2nd valve body, 27' ... 1st valve body, 28 ... 2nd valve seat, 28 '... 1st valve seat, 29 ... 2nd rod, 29' ... 1st rod , 30 ... Second valve body biasing spring, 30 '... First valve body biasing spring, 31 ... First piston biasing spring, 31' ... First piston biasing spring

Claims (5)

[Claims] 1. A brake operating member, a master cylinder for generating a master cylinder pressure by a brake operation of the brake operating member, a brake passage for feeding the master cylinder pressure, and the master cylinder pressure. A brake cylinder that generates a braking force for normally braking a wheel, an automatic brake actuator that is provided in the brake passage, a thrust generator that generates a thrust for operating the automatic braking actuator, and a thrust generator. The automatic brake actuator comprises a housing, a stepped hole formed of a large diameter hole and a small diameter hole in the housing, and a liquid tight and slidable movement in the large diameter hole. A large-diameter piston disposed in the small-diameter hole and a small-diameter hole slidably and slidably disposed at one end Is a small-diameter piston that abuts one end of the large-diameter piston to advance the large-diameter piston, and communicates with the output port of the master cylinder through the brake passage formed in the housing, and the one-end side of the large-diameter piston An automatic brake actuator inlet communicating with the large diameter hole, an automatic brake actuator output opening communicating with the wheel cylinder formed in the housing and communicating with the large diameter hole on the other end side of the large diameter piston, and normally open The automatic brake actuator inlet and the automatic brake actuator output port are communicated with each other and closed when the large-diameter piston moves forward in the direction of the automatic brake actuator output port, and the automatic brake actuator inlet and the automatic brake actuator output port are closed. Normally open / close valve that shuts off An automatic brake actuation signal pressure generating piston that generates an automatic brake actuation signal pressure by being brought into contact with an output rod of the thrust generator and advanced by the thrust of the thrust generator; A brake system equipped with an automatic brake device, which comprises an automatic brake operation signal pressure introduction passage introduced at the other end of the brake system. 2. The brake system with an automatic brake device according to claim 1, wherein the on-off valve is constituted by a center valve provided on the large-diameter piston. 3. A two-brake system, wherein the automatic brake actuator is provided for each of the brake passages of each of these brake systems, and the automatic brake actuation signal pressure introduction passage is provided for each of the automatic brake actuation signal pressures. The brake system provided with the automatic brake device according to claim 1 or 2, wherein the brake system is formed in a passage commonly introduced to the other end of each small-diameter piston of the automatic brake actuator. 4. The housing of each automatic brake actuator is a common housing, the automatic brake operating signal pressure introducing passage and the automatic brake operating signal pressure generating piston are provided in this housing, and each automatic brake operating signal pressure generating passage is further provided. The large-diameter pistons and the small-diameter pistons of the brake actuator are provided coaxially, and the automatic brake actuation signal pressure introduction passage is T-shaped so as to communicate with the other end of the small-diameter pistons of the automatic brake actuators. The brake system provided with the automatic brake device according to claim 3, wherein the brake system is formed in the passage. 5. The power of the thrust generator is any one of negative pressure, compressed air, hydraulic pressure, power generated by an electric motor, and electromagnetic force, according to any one of claims 1 to 4. Brake system with automatic braking device.